You were trolled. You need either Progskeet or E3 to flash a lower firmware. You can do a fast swap (with 2 HDD's) between say 4.00 OFW & your favourite 3.55 CFW. There are plenty of guides on this method in this forum, search. Kia ora.
http://www.ps3hax.net/2011/08/tutori...ofw-progskeet/